Effect of Postharvest Application of Aloe Vera Gel on Shelf Life, Activities of Anti-Oxidative Enzymes, and Quality of 'Gola' Guava Fruit.

Muhammad Adil Rehman,Leslie D Bourquin,Amjad Hameed,Muhammad Rafique Asi

doi:10.3390/foods9101361

Abstract

Guava is an important climacteric fruits in terms of taste and aroma, which contains various vital nutrients such as minerals, carotenoids, ascorbic acid, and polyphenols. At ambient conditions, it exhibits a short shelf life, which makes it difficult for marketing and subsequent storage. Therefore, it is necessary to develop procedures to extend its shelf life and conserve quality. For this purpose, an aloe vera (AV) gel coating was assessed for its potential to enhance the shelf life of guava fruits. Guava fruits coated with AV gels (0, 20, 40, 60 and 80%, v/v) were evaluated for postharvest shelf life extension, changes in quality attributes, anti-oxidative activities, and flavonoid content when stored at ambient conditions (23 ± 2 °C and 70–75% relative humidity) for 12 days. The AV gel-treated fruits showed reduced increments in total sugar, malondialdehyde, and total carotene contents compared to untreated controls. AV gel-treated fruits exhibited higher contents of ascorbic acid, flavonoids (quercetin and rutin), and total phenolics in comparison to control fruits. Moreover, AV gel-treated fruits displayed greater activities of superoxide dismutase, catalase, and ascorbate peroxidase, along with higher antioxidant capacity and higher levels of total soluble solids, than untreated fruits. These results demonstrate that AV gel coating, especially at high concentrations, can be considered an eco-friendly and non-chemical substitute treatment for maintaining the postharvest quality of guava fruit.

Highlights

The guava (Psidium guajava L.) fruit is highly palatable and a rich source of vitamin C
In treatments with aloe vera (AV) gel 60% and AV gel 80%, a gradual increase in total soluble solids (TSS) was observed until the end of the trial, which indicates that the treatments with the AV gels had slowed the respiration rate of guava fruits during the storage period
Our results indicate that AV gels maintained quercetin and rutin contents during the storage period

Summary

Introduction

The guava (Psidium guajava L.) fruit is highly palatable and a rich source of vitamin C. Brazil, South Africa, Mexico, India, Venezuela, Egypt, and Columbia are major guava-producing countries. In Pakistan, the total area of guava cultivation is 62,300 ha, producing 512,300 t of fruits per annum. Mango, and apple, guava ranks fourth in Pakistan in terms of area and production [1]. Guava fruit is a rich source of ascorbic acid (0.5–0.30 mg/g fresh weight), whose content is three to six times higher than in oranges [2]. The nutritional significance of guava is due to its high dietary value, being a source of carotenoids, polyphenols [3], pectin (0.5–1.8%), dietary fiber, vitamin A, phosphorus, niacin, calcium, iron, riboflavin, thiamine [4]

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Conclusion